I know what you're thinking: Brahms only wrote two piano concertos! True. But he also wrote a violin concerto, and an enterprising young Croatian pianist by the name of Dejan Lazic has arranged it for his instrument (Brahms (arr. Lazic): Piano Concerto No. 3 in D Major - after Violin Concerto Op. 77; Rhapsodies Op. 79; Scherzo Op. 4). Perhaps it's a bit cheeky of him to title the work "piano concerto no. 3" instead of something humbler like "violin concerto (arr. for piano)". But it works surprisingly well.
This is a long-time project of Lazic's, who said in an interview with Listen magazine that he had always loved the violin concerto, but couldn't perform it since it wasn't written for his instrument. So he resolved to arrange it for piano. This creates numerous problems. The two instruments have very different timbres. The piano is fundamentally a polyphonic instrument, while the violin is - by and large - a monophonic one. The bottom notes of a violin are only in about the middle of a piano's range. And so on. Lazic decided not to change a single note of the orchestral part, so the task he set himself was to rearrange the solo part.
This sort of project goes against many modern tendencies that try to recreate the composer's sound as closely as possible. It used to be more common to rearrange music for different ensembles. There are many reasons why modern practice prefers more faithful orchestration. We can afford it, for one thing: even community orchestras have all the instruments needed to put on nearly any work in the classical repertoire. But our slavish need to follow every jot and tittle of the composer's thoughts can be stifling. Lazic's project is a breath of fresh air.
The end result is not, admittedly, a masterpiece on the same scale as the two real piano concertos. But it is definitely worth a listen for the lover of Brahms.